Only third of convalescent plasma suitable for Covid-19 treatment

Ljubljana, 3 March - Only a third of plasma taken by the Blood Transfusion Centre from those who recovered from Covid-19 contains sufficient amounts of neutralising antibodies to be used as treatment for Covid-19, while 12% of those who recovered did not even develop antibodies.

The Blood Transfusion Centre, which handles blood transfusions and other blood products in Slovenia, has told the STA that it had taken plasma or blood from 1,800 individuals who recovered from Covid-19 since July 2020.

Antibody contents are highest in the blood or plasma of those who suffered stronger symptoms and had donated plasma within four to six weeks after the onset of illness.

Later on, the concentration of antibodies drops and the centre is trying to collect plasma within the 4-6 week window. Donors with high antibody concentrations donate plasma again within a period of three months.

"The immune response to Covid-19 is unpredictable and it is still too early to draw any conclusions about antibodies and immunity. Therefore all efforts are focused on fluctuation of antibodies and their role in protecting from the disease."

So far, the centre has issued 190 units of convalescent plasma. In Slovenia, plasma is used in treatment of Covid-19 as part of a study involving patients with immunodeficiencies, in particular for cancer patients and persons with congenital immunodeficiency disorders.

Studies show that treatment is most effective when started as soon as possible after symptoms occur, within three to seven days, and when plasma with high antibodies concentration is administered.

Studies conducted abroad show that the concentration of neutralising antibodies is low in the first seven to ten days after the occurrence of symptoms but starts to rise after that for the next two to three weeks.

However, the concentration of neutralising antibodies begins to drop already after three to four months after the person recovers, studies show.